Theresa May is braced for her Cabinet to split when the European Union rejects her demands for a sweeping free trade deal, after her senior team agreed to put off the hardest Brexit decisions until later.

Despite the Cabinet truce after months of internal division, three senior government officials said May will face her most challenging task keeping her ministers united when -- as they expect -- EU leaders formally reject the British approach.

The U.K. prime minister won the backing of her ministers to ask the EU for the most ambitious and wide-ranging trade agreement the bloc has ever signed, after a marathon eight-hour meeting at her country house on Thursday.

Rival Brexit-campaigners and pro-Europeans in her Cabinet declared themselves satisfied with the plan to pick and choose from the EU’s regulations voluntarily, which she will set out in more detail in a speech on Friday March 2.

But if the EU rejects the proposal, as it has said it will, the hardest questions will then demand answers. Those include how to solve the riddle of the Irish border, which regulators will police the future trade deal, and how customs checks will operate.

Talks with the EU in Brussels are due to turn to the future trading relationship after a summit on March 22. The two sides are aiming to wrap up the basic framework of a free trade agreement by October.

One senior official said May faces five key challenges in dealing with Brexit. The first is negotiating the deal -- both with the European Commission, which will be much tougher than before, and the cabinet. The second is planning logistics domestically in case there’s no deal, and preparing for whatever agreement follows the talks.

The third strand of work is keeping the devolved administrations such as the Scottish government on side, while the fourth is steering complex new laws through Parliament. The final task for May is ensuring the U.K. is able to make the most of the opportunities of Brexit, the official said.

Key Speech

The agreement among May’s top ministers -- who include chief Brexit-backer Boris Johnson and pro-EU Chancellor of the Exchequer Philip Hammond -- now means that May can write the speech setting out her negotiating goals.

Britain will ask to keep the bloc’s regulations “on a voluntary basis” for key industry sectors such as car-making, according to senior minister Jeremy Hunt.

“The central common understanding is that there will be areas and sectors of industry where we agree to align our regulations with European regulations -- the automotive industry is perhaps an obvious example because of supply chains that are integrated -- but it will be on a voluntary basis,” Hunt told BBC Radio’s Today program on Friday.

“It was a very positive meeting and a step forward, agreeing the basis of the prime minister’s speech on our future relationship,” May’s spokesman James Slack told reporters in London on Friday. The full cabinet will consider the blueprint next week before May reveals it to the public on March 2, he said.